Inverted incandescent mantle.



' DING. G. K. HAR i y TLB. INVBRTED INUANDBSGBNT MAN APPLICATION Hmm JUNE 30 Pam-{d Jal]- 31, 1911,'

xlvvnn'rnn INCANDESCNT MANTLE.

To 'all 4'whom 'it may concern:

Be it known that 1,'Cr1niznns KNOX llan- -nING, a citizen of the United States, residing at Chicago, in the county of Cool; and State ofllllinois, have invented ce1- tain new and useful Improvements 1in Inverted Incandes- `cent )d antles, of which 'the following is a "specification This invention relates generally to incandescent structures for lighting made by what has been' generally known yas the VVelsbach process, which consists" of impreunat-ing e knitted fabric of cotton or other'fi rous cellulose with solutions-of the refractoryearths, which areto' constitute the finished mantle.

I The dimensions of this impregnated fabric r are u's'ually from 100 to 200 per cent. greater than that of'the finished product after the.'

cellulose and other volatile matter isburned out, but 'this large structure is fashioned and formed approximately to such 4shape as will produce.' the desired: form oi the {imshed I mantle after it has been shrunken.

particularly to an My. invention relates improved construction o inverted niantles having an o en topped cylindrlcal body por.- tion andv a xemisp erical closed lower end 4 that possess advantages not attained by manufactured prior to my invention.

.Among theobjects of .m invention is to produceA an inverted mante of more symmetrical shapeY and having its lower portion consist. of av uniform "thickness of fabric without seams whereby this most useful portion of an inverted mantle can be uniformly and entirely raised to the highest incandescence. 1

To attain theseends and lother useful results I employ the features in the construction, the arrangement and configuration of the several parts as will a p ear hereinafter,V

more fully described end'c almed and shown -1n the accompany-ing drawings, which illustrate one embodin'ient-'ot` my invention and Figure 1 shows a side elevationI and Fig. 2

an end view of a finishedburned oil1 mantle. Fig. 3is'a `perspective vlcw of an elhptical piece of mantle fabric 4from which ythe lower 'A portionof-th'e mantles formed. Fig. -4

g a rspective View ofa length of knitted tu ularffabrcofwhich the upper-portion of v Specification of Letters Patent. Application filed June 30, 1909. Serial No. 505,274.

Patented Jan. 31, 1 91 1 the mantle is formed. Fig. .3 is a detail .s1-e

Vtion showing thc tubular portion and lower portion in position to he scanned together. Figli is a perspective View of a fabric ma tlc and Fig. 7 is a similar View oi a fabric mantle made in' :'tccordance with my invention and folded in a waythat maybe om ployed where it is intended to be placed in a flat envelop for the market. Fig. 8 is a detail View, enlarged about l() dianicters, ol" a section from the perpendicular side of an incandescent mantle formed from a knitted fabric,

vPrior tomy invention both upright and inverted incandescent mantles have genera'liy been made from atubular knitted fabric which has vspecial properties 'which peeuly iai-ly fitv it for the purpose of the ordinary upright mantle, The typical mantle fabric hasSS loops around a circumference of 5 inches2 and about 11 chains of loops to the 4inch of length, so that a square inch of 4fabric has more than three times as many threads running lengthwise as 'it has vtrosswise. This unequal distribution of the 'amount of thread 'materially facilitates the foi-min lof cylindricalmantles, for though theshrni age might be considered uniform in the lineal dimensions of the thread, the

-vertical shrinkage4 is only resisted by the force ofgravit-y while the pressure of the gas flame within the mantlev prevents. it from shrinking nearly as much circun'ifciexitially. lt has been demonstrated that a square section of knitted fabric best adapted for upright mantles and having the major portion of' its threads running in thefperpenilifzular direction -when burnedV olf4 and subjected to a uniform gas pressure would' produce a rec tangular section in the resultingburned out 'strueture'," having dimensions at least-fitti;

per cent. 'greater along( the lines of least resistance. lMost ofthe' inverted `mantles in practical use have been'made from tubuiar ii O knitted fabric,y the'loWer-end being formed I i by gathering the loweredgef of the tube and drawing it' to the center. `This resulted in'a :thickening or bunching of the goods at and around the center of the lower portion of the mantle. In ma quite a pertxonoff. Whole circumferenc ,"considering that @ofV the ltube had 'to bedrawninto .practicaiiy one n iss`- at thelcenteri y terial formingthef ma.

of the lower surface of the mantle, there was left at that point and in the form of plaits` and gathers for considera ble distance around that point an accumulation of material two or three times as heavy and dense 'as theI average thickness of 'a similar area of the other parts of the mantle. To obviate this, especially for heavier mantles made of conrser thread, gering has been employed; that. is from two to siX curved seams have been sewn through two adjacent layers of fabric from a point above the bottom where the diameter was to be retained, to a oint in the cent-er axis at the bottom. 'llhese gores permit a quantity of the stock 'to be cnt out and also take up some in the seams which turn in at right angles to the plane of the mantle surface. As a greater number of these gores are employed the shape ofthe sewn fabric as well as the shape of the resulting mantle after burning olf, becomes progressively more symmetrical.' But the seams running to the center of the lower portion of the mantle are objectionable and .the more seams employed the more objectionable they become, so that in -many self shaping mantles, commonly called. fabric mant-les,'the symmetry is often sacrificed by avoiding too many seams.

V In a preferred embodiment of my invention I employ a piece of tubular knitted fabric of the ordinary o r typical construc-` tion for the upper tubular part ofthe inverted mantle, No. l, Fig. 4, as shown in the drawings, and a separate elongated., disk cutA lengthwise from knitted mantle fabric, No. 2, Fig. 3, gathered'around its outer edge into a semispherical or cup shape. No. 2, is. .inserted in the edge of the tubular piece, N o. Lasshown in Fig. 5 of the draw ings, and sewn around its edges, united with the edges of the tube by'a seam, shown at 3.

In* use, the fabric is reversed, leaving a small port-ionbf the edges beyond the seam on the inside of the mantle.- The mantle may now bep'mounted on a carrying ring, No. 5, shown in'F-igs. 1 andQ, the fabric burned out and' themantle shaped and hardened in the same way as the ordinarygathered or gored mantles. The result is a mantle of perfect shape with no objectionable obstructions in the centrahpart'of. its lower surface, as illustrated in- Figs. 1 and 2. The circular seam is shown at No. Sand is of A4somewhat smaller diameter than the main cylindrical po'rtio'n of the mantle.

I do not wish to confine my invention to any particular relative' size or proportion, as the area ofthe lower surface formed below the' seam may vary to a considerable extent and the lower edge ofthe tubular portion may be drawn in -toward the center very readily and may stand in as muchas onethird the-distance to the center.

Fig. 6 illustrates aform of fabricmantle This piece,

(y I prefer .to have the from a knitted fabric, having its threadsdisgathered at the top upon an asbestos string to be tied around an inverted burner tube, and consists of the tubular body portion, No. l, and the ,lower portion made of the piece,'No. 2 lmited by thc sean'i lshown at N o. 3.

Fig.' 7 is a perspective view of a fabric mantle folded in a way to permit illustratA ing the arrangements of its parts, the lower piece, 2, being united to the tubular portion, l, by the circular seam,.3,

In illustrating my invention thus far I have shown that I prefer to use a separate piece of fabric for the bottom, but I do not wish my invention to be Strictly construed as covering only the use of' a distinctly scparate piece of fabric for the-lower portion of the mantle, a fabric ident-ical in character with that from which the tubular body made may be used but in this case the elliptical piece would have to be about twice as long as it is wide. I have found in practice that it is advantageous to use for the bottom piece a knitted fabric of a somewhat different character from vthat employed for the tubular part.

- In Fig. 8 I have shown the detailed view of a portion of a cylindrical mantle. In the original-fabric from which it was made the loops-were considerably longer in an up and down direction and were drawn together until the two sides of the loop touched each other in a lateral direction.

For the bottom pieces of my inverted mantle I prefer to use a knitted structure in which the loops of each chain are somewhat farther apart and having a. materially increased number of chains ,to the inch.

As the whole lower portions of inverted I mantles are subjected to a uniform pressure, lower portion made posed more uniformly in the direction of its length and width, in which case the disk (2 shown in the drawings) would more nearly assume the form of a true circle; but inasmuch as there is always some difference in the transverse and lineal shrinkage of knit ted mantle fabrics when they are in the form of the impregnated knitted fabric and after the volatile matter has been burned out, I

prefer to make the disk slightly oval 4or yelliptical to compensate for this' subsequent shrinkage and assure a finished mantle of the most/symmetrical shape.

Within recent years there have been some material improvements in methods of manufacturing mantles over the methods hereto'- fore referred to as the VVelsba ch process. IIn Some; cases the thorium,` in other chemical` compounds-than 'the nit-rate in aqueous solutions is employed 'and .artificial silk or threads spun from Viscous cellulose solutions are incorporated with these various thorium, '130 compounds which produce incandescent' structures that do not undergo such a severe transformation when the fabric is incinerated and in many cases ythese structures may be laced on the-burnersby the consumer an the fabricburned out and formed on the lamp onpwhich they are to be used. Y

Large quantities `of invertedmantle fab rics, madeby the ordinary process, have been delivered to -users of hydro carbonlighting systems in the form of impregnated mantle;

and known in commerce as soft mantles-or' fabric mantles. Whilemy invention is particularly applicable as applied, to mantles I burned oft' and finished in the factory, it is especiallyv desirable for fabric .mantles which are -to be burned off by the consumervvhois Without the skill and facilities of a mantle factory. y i 4 -By applying myinvention to fabrics made by the newer chemical processes, in which the shrinkage is very -much less, andthe strength ofthe resulting structure very ma'- 'terially increased, it will make a fabric i mantle which will compare favorably with tlc, fabric would befesay 15071 larger than the 'superficial area of the structure remaining 'after the volatile matter had been` burned out; but ithas been clearly pointed out that the shrinkage is verv materially different in the direction of the length and the Width of 'knitted fabric or in the directions in which the most or-the least of the threads are disposed. ,That is, a square inch of mantle fabric mayhave three `times as many threads running lengthwise as it :has crosswise and the shrinkage would be [likely to be about 50% inlineal dimensions and 20% transverselygsothat the area of aV section of impregnated fabric would be represented by its length multiplied by its width, and the area of the structure result.

ing from burningout the. same would be represented by multiplying 80% of its Width by 50% of lits length. The increased tions of inverted mantles ,as this increased.

amount of shrinkage in the-.direction of its length of tubular knitted fabric does not' interfere with uthe symmetry of ordinary up-V right mantles' or the cylindrical body porshrinkage takes i place on all sides of acylin drical body which are of equal length but AI prefer *to form the elliptical end portion. of a separate'section of knitted fabric in which the threads are dis oscd somewhat more uniformly in the di erent directions so that an elliptical shape having its major esente axis not vmore than 50% greater thanits minor axis may be employeckbut Where it Ais desn'able-to have a ,very open structure I can employ an ellipse having a length approximately twice its Width.

now described my invention,

Havin what I clqaim is: An 'inverted mantle formed fromv an elliptical shaped section of a single ,thickness cut lengthwisefroin knitted mantle fabric and an open topped cylindrical .body portion composed of tubular knitted fabric' having a major portion of its threads running lengthwise of the tube and having a I' portion to the circumference ofthe said ellip- -ticalj section.

seam` uniting the lower end of said body 2. An inverted fabric mantle composed of an elliptical shaped section of a single thickness cut lengthwise from knitted fabric 'and a tubular body portion of knitted mantle fabrichaving the outer edge of the'elliptical section united to the lower edge of the tuba? versely' around thejlower end of said body vlar body portion by a seam extendingr transportion wherebyl the increased shrinkage of I the'elliptical section in the ldirection -of its length when the fabric isburned .out will cause it to form a more nearly lhemispherical closed end portion.

, 3. An inverted mantle having a closed end portion composed of an lelliptical shaped section cut trema single thickness of'knitted i fabric and an open 'topped body portion l i formed from a tubular knitted fabric having a major portion of its threadsextending lengthwise of the tubeand having a Vseam running transversely around the lower edg of the said body portion and. unitingits edge With thec'ircumference of Vsaid elliptical end portion.

A 4. An inverted mantle consisting ofnan --open topped body portion of tubular knitted fabric and having its lower end closed by an elliptical shaped section 'of a single thickness of knitted mantle fabric having a major portion of its threads extending in. 'the direction of its major axis and having aseamj running transversely around' thelower edge of said body portionand uniting itsedge with the circumference of the said elliptical shaped section.

an open topped tubular body portion formed from'vknitted'fabric and having a'closedbottom portion formed from an .v elliptical -shaped 'section-f' of` 'a single thickness of knitted mantlelfabric attached to the lower 5. Anpiiverted fabric mantlecomposed''ofA l rac edges offthe said body portion by aseaxnh riinning transverse'llyV around said' lower-A edges and ,uniting sald edges with theV edges of the circumferencev of the" elliptical bottom portion. l, i I

6; An incandescent fabric mantle comprising 'an open topped cylindrical body` portion, formed from tubular knitted fabv more'nearlyhemispherical closed lower end rio and a closed lower end portion formed of the mantle.v s from mi ellipse-shaped section of a single ln testimony whereof7 I have Signed my thickness of knitted mantle fabric, having name to this speeilieation in the presence of l5 5 its circumference attached to the lower end twosubseribing Witnesses, this 28th day of of the said bodyY portion by a seam; Where- June, 1909.. y by the 'shrinkage in the direetion'of its length of the tubular portion results in a CHARLES KNOX HARDIN-G s'ximmetrical cylindrical body portion, and Witnesses: i 1 '10 the increased shrinkage in the length of the ALICE MAUDE FAIRCHILD, ellipse shaped lower end section results in l NANETTA L. MCCAL'L. 

